Obviously they will need to revise their theories. It wasn’t not uniform around the world obviously
It is not unreasonable to consider that not all dinosaurs were killed immediately. However, so many died that the scurrying little mammals were able to begin to grow and multiply, and probably ate up all the hadrosaur and other eggs that might have been produced after the big disaster, ultimately causing them to die out. In our lifetime we had the teaming passenger pigeons that were destroyed once their breeding population fell too low. It appeared that they needed a certain sized flock to stimulate their reproductive hormones. Perhaps the social dinosaurs had a similar mechanism and once their numbers were reduced they no longer were able to breed.